CK-12 Foundation
Ck 12: Isotopes and Atomic Mass
[Free Registration/Login may be required to access all resource tools.] Students explain the workings of a mass spectrometer, and describe how this device is used to determine average atomic mass.
Khan Academy
Khan Academy: Isotopes and Mass Spectrometry
Tutorial explains isotopes, atomic weight and how isotopes can be detected using mass spectrometry. Examples are given.
Chem Tutor
Chem Tutor: Atomic Structure: Atomic Weights and Atomic Numbers
This lesson explains many basic concepts of atomic structure. It starts with atomic mass and number and then works up to more sophisticated information on electron configuration and how each element fits into the Periodic Table.
Other
Dannen.com: Atomic Bomb Decision
This site has information about the bombings of Nagasaki and Hiroshima. The information is detailed and in depth. Contains many links to related sites.
Encyclopedia of Earth
Encyclopedia of Earth: Elements
Engaging and very informative article that explains what elements are, some of their history, how they are represented, the categories of elements, the periodic table, and how they are structured and classified.
Simon Fraser University
Chem1 Virtual Textbook: Moles and Their Uses
As part of the "Basic Atomics" section of the Virtual Textbook, this site examines moles. The information presented defines moles in relation to Avogadro's number and then goes on to describe molar mass and molar volume.